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Photon force
Radiation pressure is probably the best known of the forces that light can exert on an atom. In this case, an atom absorbs resonant light and receives a momentum kick in the direction of the laser beam. Although the atom's momentum changes again when it spontaneously emits a photon, this second kick is in a completely random direction and therefore averages to zero after many absorption-emission cycles.
Induced transitions, on the other hand, lead to a so-called dipole force. This force can be understood classically by noting that the electric field of the driving laser induces a mechanical oscillation of the atom's electron. The oscillating dipole moment that is produced experiences a force in a light field with an intensity gradient, such as a standing wave.
The sign of this force depends on the "detuning" of the laser with respect to the atomic-transition frequency. For example, when the laser frequency is lower than the atomic frequency, the induced atomic dipole oscillates in phase with the driving laser field, and the atom is attracted towards regions of high intensity just like a small piece of paper is attracted towards an electrically charged object. Hence, the dipole force can trap particles in the focal region of a "red-detuned" laser beam. For a "blue-detuned" laser (i.e. when the laser frequency is higher than the atomic-transition frequency), the dipole oscillates out of phase with respect to the laser, so the atom is repelled from the high-intensity regions.
A "blue-detuned" laser should accelerate the atoms out of the tube at great velocities. Thus creating thrust on the spacecraft.
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Links please... alot of nonstandard terminology here. Sounds fishy to me.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Now that i've had time to properly read it...
This won't work for your engine. The laser effect noted here takes place inside a laser cavity trap where the light beam bounces back and forth between mirrors. Since your rocket would have to have one open end with no mirror, this isn't going to work. You also can't have a "pinhole to make the gas leak out" like a balloon, since the molecules would all be traveling parallel to the laser light.
Also, this only works at extremely low pressures, far too low to be useful, and the laser power would have to be extreme.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Also, don't forget, lasers are very inefficient. For standard solid phase and gas phase lasers like ruby or neon, about 0.1% of your input energy goes to making light. The rest gets bled off as heat. A 40 Watt Argon ion laser requires a 720 volt, 50 amp dedicated power circuit and a water cooling system. Modern diode pumped solid state lasers can manage to get an efficiency up in the 10% range but that's about as good as its going to get.
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The heat would expand the gasses out the back end of the tube, and the laser can get its power from the solar panels or even a reactor core.
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So you are making a solar thermal engine. No need for the laser.
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You would get two advantages, the thermal exapnsion + the Photon------>ion------->acceleration from the laser.
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Okay what frequency of laser would be sufficient to ionize the gas? How efficient are these lasers? What gas are you going to use? How are you going to construct the electromagnetic nosel. Possible but the devil is in the details.
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Blue light frequencies, H2 or He,the gas is ionized like in the vasimr before being admitted to the nozzel,the nozzel can have a positve charge.
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ERRORIST - what you are forgetting is that the light is already the most efficient drive mechanism available. You don't gain anything by heating the material with the laser. Any energy that goes into accelerating ions is subtracted from the beam - you can't get something for nothing.
Also, don't forget that lasers are very inefficient - you'd be better off just heating your fuel up with an electric heater.
What your'e proposing is the basic idea behind present ion engines except that it's a lot less efficient.
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What your'e proposing is the basic idea behind present ion engines except that it's a lot less efficient.
I agree with you. However,a little modification to speed the ions up before the ions exit the backend should increase the acceleration of the craft.The laser would accelerate them further if they were contained in a tube.
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Have you read much about the modern ION engine? If you haven’t you should. I haven’t so I can’t comment to much. I don’t want to reinvent the wheel. I also haven’t done the math so I don’t know how efficient you scheme is. If you want to try and design this it might be a good exercise. But to do this you are going to have to start learning the math and physics.
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I already have.To many variables to figure out the math. But the physics part should work.
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Okay, quize. What is the divergence of a vector field?
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quize question 2:
Write down Maxwell's equations both in vector form and phasor form.
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quize question 3, qualtativly discribe the ellectrical field produced by a changing magnetic field inside a toroid.
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quize question 4, write down the equation relating the frequency of a photon to the energy of a phton.
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quze question 5, what is the force generated by accelerating one oxegen ion (o-) to half the speed of light?
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quize question 6, cosider the ions o_2^-1 and o-1 in a field of one colomb per meter square. What is the force acting on each ion and how quickly are each ion accelarated?
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Don't know how the quiz can answer the questions I am asking????? Can you relate them to what I am asking?
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The short answer is "no" Errorist
The long answer is, that your engine will have lousy efficency and small thrust. No exact calculations are required to reach this conclusion, because it is quite obvious that the laser cannot possibly impart much momentum or ionization to the fuel gas in any reasonably sized system, and the energy efficency of the whole system is obviously very poor.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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The charged grids used in modern ion engines accelerate ions with at least 99.5% efficiency. They are also becoming pretty reliable due to recent advances. Lasers are not anywhere near this efficient and are therefore inferior as a method of accelerating ions.
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Not to mention that the energy applied to the acceleration grids of an ion engine imparts linear motion almost exclusively due to pulling the ions and is very efficent. A laser on the other hand, may not impart any motion at all to a gas, and this motion will be largely random due to only pushing the molecules and the kenetic nature of gasses at temperature. If the laser strikes the gas before most of the photons have left the engine. Large lasers have proven quite problematic and as Sbird has said, are very inefficent.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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I guess it is impossible to accelerate H2 ions using such methods.
[http://www.airpower.maxwell.af.mil/airc … berds.html]http://www.airpower.maxwell.af.mil/airchro....ds.html
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